As a result of the geological investigation carried out in the State for mineral exploration and combined efforts of all the sub-sections involved with exploration work numerous mineral deposits of economic and industrial value have been categorised and described according to their industrial uses.
Cement grade limestone, shale and gypsum are required as raw materials in the cement industry. Reserves of about 430 million tonnes of cement grade limestone occurrences have been reported from a few places and deposits of shale generally occur associated with or in vicinity of the limestone deposits.
Nearly 175 million tonnes of cement grade limestone is estimated in a 20 kms long Kajrahat belt located south of Son river in district sonbhadra extending from Kota to Billi. The cement factory of Dalla is based on these deposits.
North of Son river, the Rohtas limestone belt runs through almost the entire width of the district from M.P. border to Bihar border along a strike length of about 90 kms. East of the Robertsganj-chopan road, nearly 98.5 million tonnes limestone lies between Kanach and Basuhari. The deposits near Gurma have been exploited. In the past for the requirements of Churk Cement factory, only about 25% of the above reserves occur in the hills and the rest deposits generally occur below the ground, east of Ghaghar river. West of the road the limestone is generally shaly in nature. These reserves can sustain new cement plants.
Crystalline marble deposits in Ningha hill, south of Obra in Sonbhadra contain a reserve of about 10.19 million tonnes. The deposit contains high calcium and low silica material and can also serve as a blending material in upgrading the marginal grade materials in Kajrahat and Rohtas belts.
Low silica aluminous shale deposits suitable as additives in the cement manufacture, are know from almost all the cement grade limestone areas and large reserves of the same exist.
Minerals used both as acid and basic refractories e.g., magnesite, dolomite, pyrophyllite-diaspore, quartzite, graphite, clays, andalusite and sillimanite etc, are reported from numerous areas in the State.
Fire Clays :-
Reserves of about 3 million tonnes of low PCE fire clays have been established in Bansi-Misra-Makrikhoh areas in the SW part of Sonbhadra district. These fir clays were tested in C.G.C.R.I laboratories and it was indicated that the clays alone are not suitable for any industrial purposes, due to their non-plastic nature and high porosity. The clays could, however, be use for making IS: 6 standard fir-bricks after blending with suitable plastic clay. Later some clay pockets were found in Karvi-Manikpur area of Banda/Chitrakoot district. This clay is 2 to 6 meters thick and is associated with bauxite.
Diaspore is found associated with pyrophyllite in many areas of district Jhansi, Lalitpur and Hamirpur, Generally 4 to 10% diaspore occurs in pyrophyllite, Several areas have been leased out to private parties and the mineral is supplied to various industries.
Andalusite occur as porphyroblasts (1-2 cm long and 3-5 mm wide) in the phyllite and schist, as well as placer associated with the migmatites and quartz veins traversing the phyllite, over an area of about 48 sq kms, north and west of Wydhamganj in Sonbhadra. The andalusite content in the phyllite varies from 5 to 15% by weight and the mineral contains 46-55% silica, 32-39% alumina, 3.5-4.7% iron oxide, 0.3-0.6% TiO2, about 0.5% CaO, about 0.6% Na2O, 3.3-4% K2O and 2.9-4.2% Loss on ignition.
This area is likely to contain about 13.5 million of andalusite per meter depth of the rock and the4 placer deposit extending over 1.5 sq km is estimated to contain about one million tonnes Andalusite to a depth of 4.25 meters form the surface. Due to its high iron content, the mineral would require upgrading and beneficiation , before it can be used in refractory industry.
Sillimanite occurs as prophyroblasts in the form of long prismatic crystals (0.5-17cm), a 100 meters wide zone of quartz-biotite schist rocks at Chhipiya near Babhani, south Sonbhadra constitutes roughly 15% by weight of the rock.
Mineable reserves of sillimanite upto a depth of 30 meters are estimated at 10 million tonnes, out of which 1 million tonnes (proved reserves) occur over a strike length of 0.5 km having 21.46% Al2O3, 6.6% Fe2O3 and 61.0% silica (the value of Al2O3 increase by 10% after individual sillimanite crystals are analysed separately). Due to its high iron content, the mineral would require upgrading and beneficiation, before it can be used in refractory industry.
Glass Industry :-
High grade silica sand is the basic raw material for the manufacture of various types of glass. Presently the friable high grade material around Shankargarh, Prayagraj district is mined at many localities by private parties and sent to various glass factories and foundries (as moulding sand). A glass manufacturing is also operating in the area. As a result of geological investigation carried out in parts of district Prayagraj and adjoining Chitrakoot district several sizeable deposits of glass sand have been found and reserves estimated. Large reserves of compact sandstone of other grades are also available in these areas. The State Mineral Development Corporation had also established its mines and a beneficiation plant to beneficiate and upgrade medium grade material, which is presently operated by M/s NMDC.
Aluminium Industry used bauxite, high alumina clays and diaspore etc. as raw material for the manufacture of aluminum metal. As a result of the investigations carried out in district Banda, Mirzapur and Varanasi/ Chandauli, sizeable deposits of high grade Alumina have been located in Rajahaun, south of Manikpur. Out of about 12 million tonnes bauxite, about 6 million tonnes of reserves are high grade containing >45% alumina and are suitable for aluminium industry. A part of Rajahaun deposit was mined in the past and the material was supplied to Hidalco, Sonbhadra, U.P. and Balco at Korba, M.P. In Varanasi/ Chandauli reserves of 1.5 million tonnes (G.S.I) have been estimated.
The basic elements as plant nutrient are nitrogen, potash and phosphate, which are derived from a number of naturally occurring mineral deposits. A number of other mineral are used as soil conditioner such as gypsum, limestone, pyrite etc. Deposits of phosphatic rock, gypsum and limestone occur in the State at various places.
The Directorate has carried out detailed exploration in a 6 kms long belt of rock phosphate in Pisnari-Tori areas of Lalitpur, The P2O5 content varies from 5-36%. A mineable reserve of about 6 million tonnes with 16% P2O5 run of mine material has been estimated. U.P. State Mineral Development Corporation has mined these deposits and sold the run of mine material containing over 25 % P2O5 material of use in the manufacture of elemental phosphorus and as direct fertiliser. A composite project for mining and beneficiating 3 lakh tonnes of low grade rock to produce about 1,20,000 tonnes of high grade (>36% P2O5) phosphate annually has been developed at a cost of Rs. 70 crores for these deposits.
Construction Industry :-
Apart from cement, the construction industry uses a variety of rocks and their products as basic material, such as building stone, marble, ballast, sand, morrum, brick earth, fillers and extenders for paints , lime etc, The Bundelkhand granites and Vindhyan sandstones are extensively quarried for building stone and ballast. Roofing slates are quarries form numerous places in hill districts. Sand morrum and boulders are taken out from almost all the river beds in the plain areas of the State. Brick kills are located all over the plains and brick earth is taken out from nearby land. The low grade limestone and dolomite occurring in Sonbhadra district have been mined in the past for making lime. Paints of various kinds are very important in the construction work. Pyrophyllite, Ochre and several other minerals make the bases for high quality paints. Pyrophyllite deposits are found in Jhansi, Lalitpur and Hamirpur districts, while ochres are found in district Banda/ Chitrakoot.
There are many other big and small industries which use minerals in one or the other form e.g., electronic , chemical, rubber, paper, filler, cosmetics, steel melting etc. Many of the minerals used in these industries are found in the State. A brief account of some such minerals is as follows:
- S.M.S grade Dolomite:- Geological investigation of SMS grade dolomite has been carried out by the Directorate in Bari- Bagmana, Sinduria, Chopan and Karamdand areas in Sonbhadra. A reserve of about 6.5 million tonnes suitable for steel melting shop has been established.
- Pyrophyllite:- Pyrophyllite, through chemically different have almost similar physical properties and have therefore a wide range of identical industrial uses. Various other grades of pyrophyllite is used as fillers in rubber, paper and soap etc also as polishing agent, carrier for insecticides and pesticides and as extender in paints.
Pyrophyllite along with diaspore is found associated with certain geological structures in Lalitpur, Jhansi and Hamirpur districts. 4 to 10% diaspore is present in the ore. Several private entrepreneurs and are mining in the known areas and have established small industrial units based of these minerals. The results of geological work has revealed the presence of about 0.5 million tonnes pyrophyllite in the three areas in Lalitpur district and one Hamirpur district.
- Baryte- Ground or crushed barite is used principally in oil well drilling mud and in the glass, paint and rubber industries. Crude barite is used chiefly in the lithopore and chemical industry. Baryte mineralization is known from near Mathura village in Lalitpur and about 1 sq. km area has been prospected to find out the extension of mineralization. Mineralisation in the form of veins measuring 30 mts in length and 10-20 cms thick have been established. Baryte is crystalline in nature and has 62.93% BaO and 16.9% SO3.
- Coal: About 900 million tonnes of medium to low grade coal was estimated by the Geological Survey of India in the southern and southwestern parts of Sonbhadra district. Subsequently Coal India Ltd. Carried out additional exploration and upgraded the reserves figure to 1050 million tonnes. M/s Coal India has developed large coal mines in this part and at present over 16 million tonnes of coal is annually produced from four mines located on the four seams viz., Upper Purewa, Lower Purewa, Turra and Kota. Turra seam is thickest (14-21 meters) followed by Lower Purewa 10-14 (mets), Upper Purewa (6-9 m) and Kota (2.5-4.4 m). Turra seam also contain the best quality coal (Grade II)
Base metal Investigation in Sonrai Area, district Lalitpur:-
Regional geological survey in Lalitpur and Jhansi districts had revealed the presence of base metal sulphide mineralization in several areas. A potential area near Sonraj village was eventually taken up for detailed integrated survey in collaboration with U.N.D.P. project of Mineral Surveys in U.P. As a result of the detailed work mineralized zones of 400 to 1000 meter strike length and 1 to 3 meter thickness containing 0.5 to 1% copper were delineated in the western part of the area. Another zone of mineralization containing 1.7% copper has been found in the Tori area. In the Pisnari area Uranium has been discovered along with copper mineralization. This zone is 300 meters wide and contains 0.01 to 0.09% uranium. Most of the mineralization is present at a depth of 150-500 meters from the surface. Follow up work by atomic minerals division suggests that the economic mineralization do not form continuous zone and are lenticular.
Low grade iron ore of Girar:-
About 100 million tonnes of low grade iron ore containing 25%-30% iron has been established in Berwar-Girar area of Lalitpur. The banded iron formations are intersected by basic and ultrabasic rock. Sporadic gold mineralization is associated in quartz veins within the iron formation. The low grade rock can be easily beneficiated to produce concentrates carrying 67.3 % iron.